Safety socket



Jan. 23, 1962 Filed July 8. 1960 2 Sheets-Sheet 1 45 r t n 41 5 I I III I \1 3 ZEHg-e INVENTOR. ARTHUR 6. J''MS'F/V Arr-alive?! Jan. 23, 1962 A. G. JENSEN SAFETY 30 Filed July 8. 1960 CKET 2 Sheets-Sheet 2 United States Patent ffice 3,018,350 Patented Jan. 23, 1962 3,018,350 SAFETY SOCKET Arthur Gail Jensen, 3326 N. Sacramento, Chicago, Ill. Filed July 8, 1960, Ser. No. 41,583 5 Claims. (Cl. 200-1155) This invention relates to electrical connection devices, and more particularly to a safety socket device adapted to be employed to connect an appliance to an electric outlet and being provided with means to automatically disconnect the appliance from the power lines when a short circuit develops in the appliance.

A main object of the invent-ion is to provide a novel and improved safety connection device for connecting electrical appliances to conventional power supply outlets, the device being simple in construction, being easy to install, and providing reliable protection against overloading or overheating of the supply line conductors when a short circuit develops in an applianceconnected thereto.

A further object .of the invention is to'provide an improved safety fuse device adapted to be connected between an electrical appliance and an outlet receptacle, the device being inexpensive to fabricate, being compact in size, being durable in construction, and being arranged so that the fuse element thereof may be readily replaced whenever required.

Further objects and advantages of the invention will become apparent from the following description and claims, and from the accompanying drawings, wherein:

FIGURE 1 is a perspective view of an improved safety fuse device constructed in accordance with the present invention.

of one of the fuse-retaining cap members employed in the safety fuse device of FIGURE 1.

Referring to the drawings, 11 generally designates .an improved safety device according to the present invention, adapted to be connected between an electrical appliance and an outlet receptacle associated with .a conventional domestic electrical power supply system. The device 11 comprises a generally rectangular-housing 12 of insulating material provided witha removable back cover 13, preferably of'the same material, the back cover being provided with an internally threaded, inwardly projecting fastening boss 14 which threadedly receives a fastening screw 15 :engaged through a central aperture 16 provided in the front wall 17 of the housing 12. The removable back wall '13 is formed with the thickened main body portion 13 and is further formed with a pair of integral channel elements 19, 19located adjacent the opposite ends of the cover and shapedto receive the inner edges of integral positioning ribs 20, 20 formed in the housing 12 and extending inwardly from the front wall 17 thereof, as shown in FIGURE 5. The back cover 13 is further formed with a pair of integral vertical ribs 22, 22 which are spaced inwardly from the positioning channels 19,19, as shown in FIGURE 5, and which terminate adjacent the inner ends of respective pairs of female contact elements 23, 24 supported on the front wall 17 in a manner presently to be described.

As shown in FIGURE 5, the thickened main body portion 18 of the back cover 13- fits inside the end walls 27 and 28 of the housing 12 and also fits between the top and bottom walls 29 and 30 of said housing, as shown in FIGURE 6.

The front wall 17 of the housing is integrally formed with respective female socket faces 31, 31, provided with the vertically spaced horizontal prong-receiving apertures 32 and 33. The female contact elements 23, 23 are formed integrally on a horizontally extending bar member 34 of metal, providing a common conductive connection between the female contact elements 23, 23, the metal bar 34 being secured to the front wall 17 of housing 12 by fastening screws 35, 35, as shown in FIG URE 3, and being arranged so that the resilient female contact elements 23-, 23 are positioned directly behind the apertures 32, 32. "A two-conductor line cord 36 is engaged through a grommet 37 mounted in the top wall 29 of housing 12, one of the conductors 38 being soldered or otherwise suitably connected to the metal bar 34. The remaining conductor 39 is soldered or otherwise suitably connected to a horizontally extending metal bar 40 which is mounted in the top portion of housing 12 and which is provided with apertured supporting lugs 41, 41 which are fastened to the top portion of front wall 17 by suitable fastening screws 42, 42, as is clearly shown in FIGURES 3 and 6. The respective opposite end portions of the horizontal bar member 40 extend through respective notches 43, 43 provided in the top corners of the vertical ribs 22, 22. As shown in FIGURE 5, the bar member 40 is formed with the reduced end lug portions 44, 44 which extend through and project beyond the vertical ribs 20, 20.

The remaining female contact elements 24 are integrally formed on the inner ends of respective resilient arms 45, 45, said arms being providedwith the attaching flanges 46 which are secured to the front wall 17 by fastening screws 47, 47, the spring arms 45, 45 projecting laterally from the female contact members 24, 24, as viewed in FIGURE 3, and extending through vertical slots 48, 48 formed in the ribs 20, 20. The female contact elements 24, 24 are positioned directly behind the lower horizontal slots 33, 33, in the proper relationship to receive the lower prongs of male plugs inserted into the socket faces 31, 31, with the upper prongs of the plugs received in the upper female contact elements 23, 23.

Secured on the free end portions of the spring arms 45, 45 are the respective metal cup members 50, 50, of proper size to receive the conductive end terminal portions of respective elongated cylindrical fuses 51, 51.

Designated at 52, 52 are respective removable cap members of insulating material which are formed with cylindrical reduced main body portions 53, 53 which are rotatably engageable in respective generally circular apertures 54, 54 provided in the top wall 29 of housing 12 in vertical alignment with the cups 50, 50. The top circular flange portion of each cap 52 is suitably knurled to facilitate grasping the caps, as is shown in FIGURES 1, 3 and 6. Mounted in each cap 52 is a downwardly facing, generally U-shaped resilient clip element 54, havgage the top end terminal portions 58 of the cylindrical fuses 51 in the manner clearly illustrated in FlGURE 3. Thus, the fuses 51 may be inserted through the apertures 54 with the cap members, the cap members being suitably oriented so that their lug elements 55 will pass through the notches 57, the bottom end portions of the fuses 51 being received in the cups t} and the fuses being pushed downwardly against the spring force of the contact arms 45. The cap members 52 may be then rotated 180 from their positions of insertion to engage the lugs 55 beneath the end portions 44 of the conductive bar 40, whereby to lock the cap members, while at the same time establishing an electrical connection from the spring arms 45 to the bar member 40 through the respective fuses 51. Said fuses are thus placed in series between the line conductor 39 and the respective female contact elements 24, 24.

As will be readily apparent, when an appliance is connected to the domestic power supply conductors through the device 11, if the appliance becomes overloaded sufficiently to exceed its current rating, the associated fuse 51, which is of a proper size to melt when said current rating is exceeded, blows, disconnecting the appliance from the line. This prevents overloading of the power supply line, while allowing the use of other appliances connected to said power supply lines while the defective appliance is disconnected therefrom.

As will be readily apparent, the use of devices 11 in conjunction with respective appliances will provide individual protection for each of the appliances, so that a defective appliance may be readily located, and so that the short circuiting of one appliance will not prevent other appliances connected to the same branch of the supply system from being used.

As above mentioned, the fuses 51 are preferably of lower current ratings than the main fuses of the system, corresponding to the maximum safe current ratings of the individual appliances with which the device 11 is to be used. This insures that the fuses 51 will blow before the main fuses of the supply system.

In order to replace the fuses 51 it is merely necessary to rotate their associated caps 52 180 from the positions thereof shown in FIGURE 3, whereby to bring the projections 55 in vertical alignment with the notches 57, allowing the caps 52 to be elevated and to extract the fuses 51 from housing 12. The fuses may be readily replaced and mounted in their operative positions, shown in FIGURE 3, by merely following a procedure reverse to that above described.

As shown in FEGURE 2, the ribs 22 are provided with notches 60 at their lower portions receiving and providing clearance for the rear longitudinal edges of the spring arms 45, 45. As further shown in FIGURE 3, the slots 48 are of substantial height, allowing for substantial vertical flexure of the spring arms 45, the tension of said spring arms acting upwardly on the fuses 51 to hold the lugs 55 firmly in conductive contact with the opposite end portions of the conductor bar 40.

While a specific embodiment of an improved safety fuse device has been disclosed in the foregoing descrip tion, it will be understood that various modifications within the spirit of the invention may occur to those skilled in the art. Therefore, it is intended that no limitations be placed on the invention except as defined by the scope of the appended claims.

What is claimed is:

1. A safety fuse device comprising a housing, a twoterminal female socket mounted in said housing and having a pair of prong-receiving resilient cont-act elements, a spring arm connected to one terminal of said socket, a conductor bar rigidly mounted in said housing, an insulating abutment element mounted in said housing transverse to and supportingly engaging said conductor bar and terminating rearwardly adjacent said resilient contact elements, a removable cap member extending into said housing opposite said spring arm, a conductive clip element mounted in said cap member and being lockingly and conductively engageable with said conductor bar, a fuse mounted between and conductively connecting said clip element and said spring arm, and a two-conductor line cord having one conductor thereof connected to said conductor bar and the other conductor thereof connected to the remaining terminal of said female socket.

2. A safety fuse device comprising a housing, a twoterminal female socket mounted in said housing and having a pair of prong-receiving resilient cont-act elements, a spring arm connected to one terminal of said socket, a conductor bar rigidly mounted in said housing, an insulating abutment element mounted in said housing transverse to and supportingly engaging said conductor bar and terminating rearwardly adjacent said resilient contact elements, a removable cap member extending rotatably into said housing opposite said spring arm, a conductive clip element mounted in said cap member, said clip element having an outwardly projecting end portion lockingly and conductively engageable with said conductor bar, a fuse mounted between and conductively connecting said clip element and said spring arm, and a two-conductor line cord having one conductor thereof connected to said conductor bar and the other conductor thereof connected to the remaining terminal of said female socket.

3. A safety fuse device comprising a housing, a twoterminal female socket mounted in said housing and having a pair of prong-receiving resilient contact elements, a spring arm connected to one terminal of said socket, a conductor bar rigidly mounted in said housing, an insulating abutment element mounted in said housing transverse to and supportingly engaging said conductor bar and terminating rearwardly adjacent said resilient contact elements, a removable cap member extending rotatably into said housing opposite said spring arm, a conductive clip element mounted in said cap member, said clip element having an outwardly projecting end portion lockingly and conductively engageable with said conductor bar, said spring arm being provided at its free end with a contact cup opposing and axially aligned with said clip element, an elongated fuse having end terminals respectively engaged in said clip element and contact cup and conductively connecting said clip element and said spring arm, and a two-conductor line cord having one conductor thereof connected to said conductor bar and the other conductor thereof connected to the remaining terminal of said female socket.

4. A safety fuse device comprising an insulating housing having a front wall, a rear wall parallel to said front Wall and peripheral walls connecting the edges of said front and rear walls, a plurality of parallel ribs formed in said rear wall and extending toward said front wall, respective pairs of vertically spaced female contact elements secured to said front Wall and terminating adjacent said ribs, said ribs being formed with aligned notches at their top inner corners, a metal bar secured to said front wall transverse to said ribs and received in said notches, respectively conductive spring arms secured to the lowermost of the female contact elements and ex tending laterally in said housing, respective removable cap members extending rotatably into said housing opposite said spring arms, conductive clip elements mounted in said cap members and having outwardly projecting end portions lockingly and conductively engageable beneath said metal bar, respective fuses mounted between and conductively connecting said clip elements and said spring arms, and respective terminal members connected to said metal bar and the upper female contact elements.

5. A safety fuse device comprising an insulating housing having a front wall, a rear wall parallel to said front wall and peripheral walls connecting the edges of said front and rear walls, a pluraiity of parallel ribs formed in said rear wall and extending toward said front wall, re-

spective pairs of vertically spaced female contact elements secured to said front wall and terminating adjacent said ribs, said ribs being formed with aligned notches at their top inner corners, a metal bar secured to said front respective conductive spring arms secured to the lower- Wall transverse to said ribs and received in said notches, most female contact elements and etxending laterally in said housing, respective removable cap members extending rotatably into said housing opposite said spring arms, conductive clip elements mounted in said cap members and having outwardly projecting end portions lockingly and conductively engageable beneath said metal bar, said spring arms being provided at their free ends with contact cups opposing and axially aligned with the clip ele- References Cited in the file of this patent UNITED STATES PATENTS 2,508,770 Oshinsky May 23, 1950- 2,667,547 Lindeman Jan. 26, 1954 2,733,314 Schmidt Jan. 31, 1956 2,875,295 Lindeman Feb. 24, 1959 

